The present invention relates to a wireless terminal device, a communication method, and a computer-readable recording medium.
In 802.11, which is approved as a wireless LAN standard by IEEE, a physical layer and a MAC layer are defined. The MAC layer is a subset of a data link layer that is positioned above the physical layer in an IP-based network.
After its initial standardization, IEEE802.11 has undergone standardization of IEEE802.11b (a maximum of 11 Mbps) and IEEE802.11g (a maximum of 54 Mbps) which are high-speed wireless LANs that use 2.4 GHz band as well as IEEE802.11a (a maximum of 54 Mbps) which is a high-speed wireless LAN using 5 GHz band, and is now widely and generally available. In addition, standardization of IEEE802.11n for realizing a high throughput of 100 Mbps or higher is under consideration.
The network topology of IEEE802.11 is of two types: an ad-hoc network and an infrastructure network. An ad-hoc network is a network configuration that consists of two or more wireless terminal stations called stations (STA), which communicate with each other in a peer-to-peer manner.
On the other hand, an infrastructure network is a Basic Service Set (BSS) network that consists of a wireless base station called a wireless access point and one or more wireless terminal stations that connect to the wireless access point. Typically, the wireless access point is connected with a network. Thus, the wireless terminal stations can communicate with a communication device on the network via a wireless access point with which a connection relation has been established.
To have a wireless terminal station connected to a wireless access point, a user is required to make connection settings with the wireless access point and the wireless terminal station. For the wireless access point, a Service Set ID (SSID) of that access point and security information should be set. Here, the security information is an encryption method and secret information, may be a WEP key, for example. The SSID and security information of the wireless access point are also set on the wireless terminal station.
Because making such connection setting is difficult for “non-techie” users, some wireless access points have a SSID and security information already set at the time of sale and indicate the values thereof in their manual or on their housing.
Also, some wireless terminal stations receive a beacon transmitted from a wireless access point and display the SSID of the wireless access point, availability of security setting, received signal strength, connection condition and the like in the form of icons. When a number of wireless access points exist near a wireless terminal station of this type and the wireless terminal station receives beacons from those wireless access points, it displays icons corresponding to the respective wireless access points.
When the user selects an icon corresponding to an access point to which the user wants to connect from among displayed SSIDs, the wireless terminal starts establishment of connection with the wireless access point having that SSID and displays a wireless LAN setting screen as necessary. Connection setting is completed by the user inputting necessary information, such as security information (e.g., a WEP key), on the setting screen.
As described, wireless LAN systems are known that allow even users unfamiliar with computing techniques to easily make connection settings by preparing means for setting that are based on a Graphical User Interface (GUI) using icons.
In a wireless LAN system, a user may encounter a problem of becoming unable to perform communication on a wireless terminal station that was initially functioning normally. As this problem can result from various causes such as a failure of the wireless terminal station or a failure of the wireless access point, the user has to check various pieces of information to find out the cause of the problem. The cause of such a problem is tracked down in the following procedure, for example.
Step 1: check whether the wireless terminal station is receiving radiowave from the wireless access point. For example, it is checked whether an icon for the wireless access point to which connection should be established is being displayed on the wireless terminal station.
Step 2: check whether settings relating to a wireless LAN between the wireless terminal station and the wireless access point are correct. For example, it is checked whether connection can be established by clicking an icon.
Step 3: check IP-related settings of the wireless terminal station. For example, it is checked whether the IP address of a wireless interface has been set.
Step 4: check IP-related settings between the wireless terminal station and the wireless access point. For example, IP connectivity with the wireless access point is checked using Ping command or the like.
Step 5: check functions of the wireless access point relating to IP transfer and functions of individual applications on the wireless terminal station. For example, activate a Web browser to see whether a desired Web page can be displayed or activate mailing software to see whether mail transmission/reception is possible.
Through such tracking down, any step that is not normally functioning is detected. It shows that there is a problem at a point corresponding to such a step.
In addition to being performed by the user him/herself, such tracking down of the cause of a trouble as described above may be performed by the user calling a help desk for the wireless terminal station, wireless access point, or an Internet Service Provider (ISP) to find out the cause of the problem according to instructions from an operator there. The procedure of tracking down in this case is basically the same as the above-described one.
There are also known wireless communication devices that present a user with the cause of a failure based on information resulting from scanning of a wireless terminal station. For example, if a wireless communication device of this type does not receive a beacon including SSID that is set on the wireless terminal station, it estimates that “outside coverage area” is the cause of the failure (see JP-A 2006-33251 (KOKAI), for instance). A method has been also proposed that observes received signal strength from wireless access points in order to solve a connection failure of a wireless terminal station (see JP-A 2007-134748 (KOKAI), for instance).
As mentioned above, when there is a trouble associated with communication on a wireless terminal station, the user is required to identify the cause of the trouble by taking several steps. Steps of the procedure for identifying the cause include the necessity to check if a wireless access point to which connection should be established is displayed on the wireless terminal station or not, as described in step 1 above.
However, when a wireless LAN system is used in an apartment house, for example, a wireless access point may be installed by a resident of a neighboring room or a room below or above the user's room. In such a case, such wireless access points in neighborhood are displayed on the user's wireless terminal station in addition to the one installed by the user.
In such a case, the user needs to find the wireless access point the user has installed from a number of wireless access points displayed. A wireless access point has to be identified by a SSID that is set for each wireless access point, but the following problem can arise in this case.
To save users from making settings, wireless access points are sometimes sold with a SSID already set. That is to say, a SSID has been set by a wireless access point manufacture instead of being set by the user. In such a situation, when multiple wireless access points from the same manufacture are displayed on a wireless terminal station, the user cannot identify the one he/she installed.
Or even when the user sets a SSID by himself, the user may forget the SSID. The problem of being unable to identify a wireless access point also arises in that case as described above.
Or when a wireless access point installed by the user is in stealth mode, its SSID is not displayed on a wireless terminal station. Stealth mode refers to a mode in which a wireless access point transmits a beacon that does not indicate the SSID of the wireless access point.
Furthermore, when a configuration that installs a large number of wireless access points to secure a large area within which wireless terminal stations can make connection is adopted, such as in an office, it is impossible to identify which one of wireless access points displayed on a wireless terminal station represents a certain wireless access point.
Conventional wireless communication devices cannot solve such problems that arise when a SSID is not known as described above because they require presetting of a SSID on a wireless terminal station. Furthermore, in an environment in which a plurality of wireless access points are installed, it is impossible to identify from which wireless access point radiowave being observed by a wireless terminal station is physically transmitted.